Saturday, March 13, 2010

ch 41

The body is capable of catabolizing many substances as sources of energy. Which of the following would be used as an energy source only after the depletion of other sources?

Protein in muscle cells

An animal that migrates great distances would obtain the greatest benefit from storing its energy as

Fats

Some nutrients are considered “essential” in the diets of certain animals because

They cannot be manufactured by the organism

Animals require certain amino acids in the diet. An amino acid that is referred to as nonessential would be best described as one that

Can be made by the animals body from other substances

Which of the following vitamins is correctly associated with its use?

Vitamin A- incorporated into the visual pigment of the eye

Which of the following is a fat-soluble vitamin?

Vitamin A

Which of the following minerals is associated with its use in animals?

Calcium- construction and maintenance of bones

If the digestive system of animals are to provide the energy needed for ATP and biosynthesis, which of the following diets would be most suitable?

a diet that matches the “food pyramid” for the species

Some of the vitamins and minerals in a supplement are found at less than 100%. Which is the most likely explanation?

It is dangerous to overdose on Vitamins such as A and K.

After careful examination of the table, which of the following groups would you expect to benefit most from this supplement?

Senior citizens

Folic acid supplements have become especially important for pregnant women. Why?

Folic acid deprivation is associated with neural tube abnormalities in a fetus.

With which of the following is excessive iron absorption most likely to be associated?

Genetic disorders such as hemochromatosis

During the process of digestion, fats are broken down when fatty acids are detached from glycerol. In addition, proteins are digested to yield amino acids. What do these two processes have in common?

They involve the addition of a water molecule to break bonds (hydrolysis).

To leave the digestive tract, a substance must cross a cell membrane. During which stage of food processing does this take place?

Absorption

Intracellular digestion of peptides is usually immediately preceded by which process?

Endocytosis

Increasing the surface area directly facilitates which of the following digestive processes?

Absorption, Elimination

Which of the following is an advantage of a complete digestive system over a gastrovascular cavity?

Specialized regions are possible

Extracellular compartmentalization of digestive processes is an evolutionary adaptation in many animal phyla. Which of the following phyla is correctly paired with the compartment that first evolved in that phylum?

Annelida- complete alimentary canal

Foods eaten by animals are most often composed largely of macromolecules. This requires the animals to have methods for which of the following?

Enzymatic hydrolysis

Which of the following describes peristalsis in the digestive system?

Smooth muscle contractions that move food through the alimentary canal

After digestion, the first type of macromolecule to be worked on by enzymes in the human digestive system is

Carbohydrate

What is the substance of salivary amylase?

Starch

Which of the following statements is true of mammals?

The epiglottis prevents food from entering the trachea

What part of the digestive system have secretions with a ph of 2?

Stomach

Which of the following statements describe pepsin?

It begins the hydrolysis of proteins in the stomach

Without functioning parietal cells, which of the following would you expect for an individual?

Not to be able it initiate protein digestion in the stomach

Which of the following is true of bile salts?

They emulsify fats in the duodenum.

Most nutrients absorbed into the lymph or bloodstream are in which form?

Monomers

Which of the following enzymes has the lowest pH optimum?

Pepsin

Where are the agents that help emulsify fat produced?

Liver

Where does the complete digestion of carbohydrates occur?

Small intestine

Where does the digestion of fats mostly occur?

Small intestine

Which structure is home to bacteria that produce vitamins as by-products of their metabolism?

Large intestine

How does the digestion and absorption of fat differ from that of carbohydrates?

Which of the following is a nutritional monomer that can be transported in the blood?

Fatty acid

In which blood vessel is glucose concentration likely to vary the most?

Hepatic portal vessel

Which of the following glandular secretions involved in digestion would be most likely released initially as inactive precursors?

Protein- digesting enzymes

Adult lampreys attach onto large fish and feed regularly on their body fluids. Given this continues supply of food, which one of the following is most likely missing in lampreys?

Stomach

Which of the following would probably contribute to constipation? A substance that

Promotes water reabsorption in the large intestine

Numerous adult humans are currently treated for reflux disorders. However, at an earlier time in medical history these same individuals probably would have been diagnosed with gastric ulcers. Which of the following has mostly contributed to correct diagnosis of this problem?

Ability to diagnose and treat H. pylori infection

A hiatal hernia affects the function of the smooth muscle between the esophagus and the stomach. The hernia would be most likely to increase the frequency of which of the following?

Gastric reflex

Bacteria are beneficial to animal nutrition, including that of humans. Which of the following is among their greatest benefit to us?

Production of biotin and vitamin K

The pH of the gastric juice of the stomach is about 2 due to the formation of HCL. Where does this formation of HCL occur?

In the lumen of the stomach

The pH of the stomach is low enough and the protease activity high enough that the cells of the stomach itself are at a risk of self-digestion. This is prevented by which of the following?

Mucus secretion and active mitosis of epithelial cells

In general, herbivorous mammals have molars modified for

Grinding

In which group of animals would you expect to find a relatively long cecum?

Herbivores

Which of the following are adaptation to a carnivorous diet?

Bile salts

Why are cattle able to survive on a diet consisting almost entirely of plant material?

They have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Physical anthropologists locating the jaw bones of previously unknown vertebrate animal fossils are often able to assess the animal’s diet especially because of clues from which of the following?

The prevalence of specific kinds of teeth

In which of the following would you expect to find an enlarged cecum?

Rabbits, horses, and herbivorous bears

Coprophagy allows some animals to re-eat fecal material in order to recover more nutrients. IN which of these animals would such a behavior be displayed?

Rabbits and their relatives

Microbial symbionts are especially important for nutritional support in which of the following?

Herbivores and omnivores

Mouse mutations can affect an animal’s appetite and eating habits. The ob gene produces a satiety factor ( the hormone leptin). The db gene product is required to respond to the satiety factor (the leptin receptor).

Leptin is a produce of adipose cells. Therefore, a very obese mouse would be expected to have which of the following?

Mutation of ob or db.

Most obese humans produce normal or increased levels of leptin without satiety. Which might provide an animal an answer to at least some human obesity if a means to do so is found?

Activation of receptors for leptin

PKU (phenylketonuria) is a hereditary condition in which infants and young children cannot ingest any more than tiny amounts of the amino acid phenylalanine without serious neurological results. This damage can be prevented by a severe restriction of phenylalanine in the diet. Which of the following is the nutritional concept that forms the basis for this preventive treatment?

Essential nutrients

Which of the following occurs when digestion of organic molecules results in more energy-rich molecules that are immediately by the animal?

The excess is stored as glycogen

Which of the following hormone actions will occur when more energy is required by a human?

Blood glucagon increases

When more energy sources are needed that are generated by the diet, in which order does the animal draw on stored sources?

Liver glycogen, muscle glycogen, fat

Obesity in humans is most likely to contribute to which of the following?